The inventive concept relates to methods of operating a storage device. More particularly, the inventive concept relates to adaptive copy-back methods for selectively performing copy-back operations in consideration of storage device performance. The inventive concept also relates to storage devices operating in this manner.
Advances in the design, manufacture and operation of non-volatile memory devices has enabled, for example, the replacement of the conventional hard disk drive (HDD) with the solid state drive (SSD). The SSD typically arranges a plurality of non-volatile memory devices according to a plurality of channels. The data storage space provided by the non-volatile memory devices of the SSD must be routinely managed to ensure efficient storage of data. Such management includes a so-called “garbage collection” process.
The garbage collection process essentially reallocates (or recycles) available memory space into larger and more useful memory blocks by consolidating a number of smaller or fractured memory blocks. One or more copy-back operations are required to perform the garbage collection process. Unfortunately, a data access bottleneck to a buffer memory in the SSD may occur when non-volatile memory devices associated with multiple channels seek to simultaneously perform copy-back operations as part of overlapping garbage operations. This bottleneck may dramatically reduce performance of the SSD.